PLATE VI. 



Figures magnified 250 diameters. 



Pagk. 



Clostebium Dian.«;, . . . . . .47 



Clostbrium turgiddm, ..... 43 



Clostebium striolatum, . . . . .44 



Closterium Delpontii, ..... 45 



Closterium didtmoticum, . . . . .41 



Closteritjm subcostatom, ..... 43 



Clostebium Lunula. Var. striatum, . . . 42 



Figs. 13, 14. Clostebium ensis, . . . . . .40 



" is, 16. Closterium prelongum, . . . . 43 



Fig. 17. Clostebium Bbebissonh, (Addenda, p. 172), . . 24 



FiKs. 18, 20. Closterium LANCEOLATUM, (also Plate IX, fig. 14), . . 40 



Fig. 21. Closterium juncidum, Var. gracillima-loevissima, . 39 



" 22. Closterium peonum, . . . . .50 



